In grocery retail stores, it is common that products that may be expected to be of lower quality, e.g. products approaching their “best before” date, are offered to consumers at a discounted price. Hence, since standardized machine readable patterns (e.g. barcodes) are assigned to each product and not to each individual good, it is not possible to merely change the price in the store's computer system, but such products have to be physically identified and manually re-labeled to indicate the discounted price. This is a time consuming process.
Furthermore, there may be other reasons than time for products to degrade in quality, such as e.g. being subjected to an increased temperature.
Hence, there is a need for a device which may be used to automatically indicate an expected quality of a product, and preferably also update an indicated price as a function of the expected quality.
EP 1 720 188 A1 discloses an electrochemical timer device having a source and a drain contact. The device further comprises a switch channel and a delay reservoir that are electrochemically interconnected with a gate electrode. The switch channel interconnects the source and drain contacts and is arranged to change electrical conductivity upon electrochemistry therein, and an electrochemical reaction is arranged to occur in the gate electrode and delay reservoir upon application of a drive voltage there between. The delay reservoir is arranged such that the electrochemical reaction occurring therein gradually moves towards the switch channel and eventually reaches the switch channel after a delay time thereby changing the electrical conductivity of the switch channel.
EP 1 862 786 A1 discloses a device, kit and method for monitoring a history of an external parameter, wherein a consumption process of one electrode is controllable by an amount of consumption of another electrode, and wherein the electrodes are in contact with different electrolytes, such that consumption rates of the electrodes present different dependencies on the external parameter.
While such a device can be used to deduce if and when a certain condition has occurred, and thus may be useful for many applications, it may be too complex for other applications. Furthermore, it requires some processing in order to convert the data contained in the device into information that can be readily understood by a user.
Hence, there is a need for a more simple device.